In recent years, various techniques are being developed to impart functionality to a treatment object member by use of supercritical fluid. The supercritical fluid, which is a fluid placed under temperature and pressure of a critical point or more, has the feature of having both diffusivity of gas and solubility of liquid. Among such supercritical fluids, particularly, supercritical carbon dioxide is excellent as solvent since it vaporizes at the critical point or lower, and thus has been actively examined for uses such as dyeing, plating, or water-repellent coating to resin sheet, resin film or the like.
On the other hand, the hot isostatic press treatment, which is a technique for treating a treatment object while maintaining high temperature and high pressure, is used, for example, for processing or formation of cemented carbide, ceramics, and superalloy.
Both the high-pressure treatments are performed within a pressure-resistant container provided with a pressure resisting structure. Since these treatments are generally performed in a high-temperature state, rapid heating or cooling of the pressure-resistant container or maintaining of the temperature of the pressure-resistant container is needed to rapidly perform the treatments.
For example, Patent Literature 1 discloses a high-pressure treatment apparatus, including a pressure-resistant wall surrounding a treatment chamber and a jacket provided outside it, in which the treatment chamber is heated or cooled by supplying a heating medium into the jacket. This apparatus has the potential to enhance the heating rate or cooling rate within the treatment chamber by heating or cooling the heating medium in addition to heating or cooling of a pressure medium fed into the treatment chamber.
On the other hand, Patent Literature 2 discloses a high-pressure treatment apparatus, including a pressure-resistant wall and an inverted cup-shaped partition wall provided inside it, in which a treatment chamber is formed inside the partition wall. In this apparatus, a partitioned chamber is formed between the partition wall and the pressure-resistant wall, and the treatment chamber is heated by supplying a nonreactive gas such as argon gas to the partitioned chamber as heating medium.
However, the related art as described above has the following problems to be solved.
In the apparatus of Patent Literature 1, the large thickness of the pressure-resistant wall inhibits transfer of heat from the heating medium to the treatment chamber since the inside of the pressure-resistant wall is heated or cooled from the outside of the pressure-resistant wall. This inhibits the reduction in heating time or cooling time of the pressure-resistant container.
The high-pressure treatment apparatus of Patent Literature 2 has a limitation in the reduction in volume of the partitioned chamber since a heater for heating the heating medium is provided within the partitioned chamber. This leads to increase in overall size and complication of the high-pressure treatment apparatus.